Select Non Stop Play, select Song List Editor, then down in the lower right hand corner SONG LIST with Arrows on both sides, I have PC version, use arrow left or right to select the song list you want to add songs to, then check off the songs you want to add to that list.
I feel dumb, but how do you add and remove songs from the Song List 1, 2, 3, 4, in RS Remastered ? I have no problem with adding songs to the favorites list, but can't figure out how to add them to the Song list 1-4.